1. Field of the Invention
This invention pertains to improvements in controlled heat treating. More particularly, this invention pertains to an infrared hub treat source with controlled cooling.
2. Description of the Prior Art
The use of fluidized bed furnaces for heat treating a product is well known. Such furnaces generate an extremely hot bed of fluidizing particles such as aluminum oxide. The furnaces can be used for both continuous processing of a product or batch processing of products.
U.S. Pat. No. 4,752,061 teaches a fluidized bed furnace which uses infrared radiation as the heating source. One advantage of using infrared radiation as the heating source is that it permits the use of inert gases to fluidize the particles in the furnace. As a result, a controlled atmosphere can be provided surrounding the product being heat treated in the furnace.
The aforesaid U.S. Pat. No. 4,752,061 places infrared lamps out of the bed behind a quartz wall or screen. As a result, the distance from the infrared lamps to the bed results in a high temperature gradient with too little of the energy source contributing to the fluidization of the bed. This leads to significant energy inefficiency. Also, the infrared lamps may be in close proximity to the stainless steel retort. This could result in partial melting of the retort.
In the present invention, infrared lamp heat treating assemblies are utilized including infrared sources disposed within transparent conduits. The present invention utilizes means for admitting the cooling fluid to the interior of the conduits.